1. Field of the Invention
The present invention relates to a welding robot gun connecting device for connecting a cradle of a welding gun to a robot wrist.
2. Description of the Related Art
A conventional welding robot gun connecting device for connecting a welding gun to a robot wrist is illustrated in FIG. 3.
A cradle 25 has a pivoting portion 24 at a front end thereof for pivoting welding gun arms 22 and 23 which are respectively operated to be opened or closed by a pressure cylinder 21 and an electrical transformer 26 connected thereto at a rear end thereof. The electrical transformer 26 has a rear end connected to a robot wrist 28 by way of a connecting bracket 27. The connecting bracket 27 has both ends respectively provided with flanges 29 and 30 to which bolts are attached. The electrical transformer 26 and the bracket 27 are connected to each other by bolts 31 screwed from the flange 29 while the robot wrist 28 and the bracket 27 are connected to each other by bolts 32 screwed from the flange 30.
However, there was a problem that the welding robot gun is disposed at the position remote from the robot wrist since there is defind a gap between the flanges 29 and 30 for the interval corresponding at least to the length of the bolts, i.e., the interval where the bolt 31 can be screwed into the flange 29 and the bolt 32 into the flange 30 when the welding robot gun is connected to the robot wrist by way of the flanges 29 and 30 provided at both ends of the connecting bracket 27.
There was proposed a connecting device for connecting the robot wrist 28 to the cradle 25 as illustrated in FIG. 4 by fixing flanges 33 and 34 to the robot wrist 28 and the cradle 25, and thereafter screwing bolts 35 into both the flanges 33 and 34.
There was another problem in the proposed connecting device that the bolts 35 are disposed at the portion projecting outwardly from the robot wrist 28 and the cradle 25 when both the flanges 33 and 34 are connected by the bolts 35 although the welding robot gun can be disposed close to the robot wrist 28, which involved an increase of the size of both the flanges 33 and 34.